The invention relates to an apparatus for winding or unwinding material webs onto or from a winding core in accordance with the preamble to claim 1.
In printing works, it is known for products which occur in web form, such as paper webs, to be wound up on a winding core or unwound from a winding core.
The disadvantage with such known winding cores is the fact that they have a relatively large diameter in order to ensure the minimum winding or unwinding speed of the web-like product. A further disadvantage, caused by the large diameter, is the high weight and the high moment of inertia of the winding core.
The present invention is based on the object of providing an apparatus of the type cited at the beginning which makes it possible to achieve a higher winding speed with a smaller winding-core diameter.
According to the invention, the object is achieved by an apparatus having the features of claim 1.
The subclaims 2 to 11 relate to further, advantageous refinements of the invention.
The object of the invention is in particular achieved with an apparatus for winding or unwinding material webs onto or from a winding core, especially paper, textile, plastics or other material webs, comprising a bearing device for the winding core and a drive and a torque-transmitting device, coupled to the latter, for driving or braking the winding core rotatably mounted in the bearing device, the torque-transmitting device comprising a toothed-belt reduction gear mechanism operatively arranged between the drive and the winding core.
The toothed belt reduction gear mechanism has the advantage that it can be operated at a significantly higher speed than gear mechanisms known hitherto for driving winding cores, the toothed-belt reduction gear mechanism also being capable of transmitting a high torque to the winding core. As a result, the use of a winding core with a low diameter is possible, it being possible for this to be operated both at a high speed and also with a high torque. In particular when only a few webs are resting on the winding core, there is the requirement for the winding core to be operated at a high speed in order to achieve the necessary web speed. The winding operation is preferably operated in such a way that a constant force on the web is produced. It follows from this that, with increasing diameter of the coil, a higher torque is necessary in order to produce the required, in particular constant, web tension.
The fact that the torque-transmitting device comprises a toothed-belt reduction gear mechanism means that the drive can be carried out at significantly higher speeds than in the gear mechanisms, common hitherto, which permit a maximum input drive speed to the gear mechanism of only about 6000 rev/min. The reduction has the effect of a higher torque available at the winding core. In addition, toothed-belt gear mechanisms are cheaper to produce than cog gear mechanisms and are less problematic to maintain, since the lubricating and cooling problems which result in the case of cog gear mechanisms which produce heat are dispensed with. Toothed-belt gear mechanisms are also lighter than cog gear mechanisms, as a result of which lighter device designs are possible.
An additional advantage of the winding cores of low diameter is the fact that they have a low weight and a low moment of inertia. In addition, the winding core has a greater holding capacity but, given a predefined maximum external diameter of the roll, a longer paper web can be wound up. This is advantageous in particular in the case of small wound rolls, for example in the case of paper rolls.
In a particularly preferred embodiment of the apparatus of the invention, this has a bearing device for the winding core which is configured as a bearing fork and is mounted such that it can pivot about an axis of rotation between at least two positions, one of the positions corresponding to the working position, in which the winding or unwinding operation takes place, and the other, in particular horizontal, position being provided for the insertion or removal of the winding core or a wound roll formed on the winding core. In the horizontal position of the bearing fork, the winding core provided with a gearwheel can be moved without problems into engagement with a drive gearwheel on the torque-transmitting device, since in this position, during the insertion or removal of the wound roll, there are no, or only a small, wound-roll weight component which could cause tooth-on-tooth impact. In an advantageous embodiment, the toothed-belt reduction gear mechanism is connected to the bearing fork and can be pivoted easily and without problems together with the bearing fork.